Recently, efficiencies have been realized in the digital transmission of modem signals used in facsimile calls by demodulation and remodulation of the page portion of the facsimile call. This enables the page portion of the facsimile call to be efficiently transmitted over a digital transmission facility. One such arrangement is disclosed in United States patent application of D. O. Anderton and R. L. Daggett Ser. No. 428,560, filed Oct. 30, 1989.
In one such prior demodulation/remodulation arrangement for transmission, the exact timing relationship between a transmission network modem signal demodulator and a transmission network remodulator was not communicated. As a result, facsimile image data was lost because of small differences in the symbol rate of the transmitting facsimile equipment and the transmission network remodulator. In one attempt at overcoming this problem, delays were interjected into the transmission to provide a buffering of the image data. However, the inclusion of such delays did not entirely solve the problem because only facsimile page, i.e., image, data of a limited duration could be transmitted. If the duration of the facsimile page data was longer than the limited duration, some of the page data transmission would be lost. Moreover, the inclusion of such delays in the transmission of digital signals is highly undesirable. Indeed, for continuous data calls, the addition of delay would not mitigate the problem at all.